Title: Study on Stress Transfer Property for Embedded FBG Strain Sensors in Concrete Monitoring

Author(s): Il-Young Jang and Ying-Wei Yun

Publication: IJCSM

Volume: 3

Issue: 1

Appears on pages(s): 33-37

Keywords: fiber bragg grating strain sensor; stress transfer rule; transfer coefficient, shear lag theory

Date: 6/30/2009

Abstract:
Fiber Bragg grating (FBG) sensors already have been the focus for structural health monitoring (SHM) due to their distinguishing advantages. However, as bare optical fiber is very fragile, bare FBG strain sensor without encapsulation can not properly be applied in practical infrastructures. Therefore encapsulation techniques for making encapsulated FBG strain sensor show very important in pushing forward the application of FBG strain sensors in SHM. In this paper, a simplified approximate method to analyze the stress transferring rules for embedded FBG strain sensors in concrete monitoring is put forward according to mechanics of composite materials. Shear lag theory is applied to analyze the stress transferring rule of embedded FBG strain sensor in measured host material at the first time. The measured host objects (concrete) and the encapsulated FBG strain sensor are regarded as a composite, and then the stress transfer formula and stress transfer coefficient of encapsulated FBG strain sensor are obtained.